During road construction or the leveling of ground, for example for buildings, parks or playgrounds, vehicle displays or the like, ground preparation machines are used which are to give a predetermined topography to the place of ground through, on one hand digging and on the other hand piling up material.
It is important in this connection that the working tools on the machines that are used can be accurately controlled to the exact right working level in the intended section. The control should preferably even be able to be remote-controlled automatically so that the desired topography in the right position inside a section should be able to be written into a computer program and information concerning suitable processing should be able to be given continuously and automatically to the driver of the vehicle. It should also, in the cases where it is possible, be able to have automatic controlling of the machines in order to perform certain work completely automatically.
This implies that for ground-working equipment one needs to keep track of the exact position in space of the working tools' positions in space, the angular position in both horizontal and vertical directions and their working directions.